More than 2 dozen trendy hotels are banding together to take on Expedia and Priceline

What it would look like to book a same-night reservation at Gramercy Park Hotel using One Night. One Night The system that many hotels use to manage their reservations is broken. Even in the most popular hotels, a large percentage of rooms go unused on any given night.

Earlier this year, Standard International — the company behind the trendy Standard hotels in Los Angeles, Miami, and New York's High Line and East Village neighborhoods — launched a new spontaneous-booking app, called One Night Standard, that makes the most of the properties' unused rooms. After 3 p.m., anyone can log onto the app and see what rooms are available for that night.

"We found that those people were some of our most loyal customers," Standard International CEO Amar Lalvani told Business Insider in August. It seemed that many of the app's users were people who lived locally but maybe wanted to have a spontaneous stay at the hotel for a special occasion or a late night at work. "What we're seeing is a merging of the hotel and tech worlds."

That venture proved so successful in making the most of unused inventory that today the hotel group announced the launch of a new app, One Night, that expands the spontaneous-booking service to other hotels.

The app functions much like One Night Standard — after 3 p.m., users can log on to One Night, scan nearby hotels that still have rooms available for that same night, then book it with just one button.

The Royal Suite at The Carlyle, a Rosewood Hotel in New York City that's available for spontaneous bookings on One Night.Facebook.com/thecarlylehotel

One Night will be a direct competitor of Hotel Tonight, a popular last-minute hotel booking app.

As Lalvani explained to Business Insider in August, the hotel industry is facing a monumental challenge from third-party booking apps and online travel agencies like Expedia and Priceline. Both Expedia and Priceline have grown in value and led a number of acquisitions in the online-booking space in recent years, but the cuts they take in the form of commission makes them serious threats to hotels.

But unlike Expedia and Priceline, One Night's interface has beautiful, large photos that highlight the hotels' design, and you don't see prices until you navigate away from the home page.

"The work that we're doing [with One Night] celebrates the hotel, and it doesn't rank by price [like Expedia]. You can comparison shop by swiping off of the home page — and that comparison is based on the experience, not by the price," Lalvani said. "Our goal was to pick hotels that we loved, that are experience-driven, and that we think other people will like."

One Night While One Night does serve a similar function as Hotel Tonight, Lalvani explains that it's set apart by the carefully curated hotel selection. The hotels were selected not because they fall in a similar price range, but because they have the same approach to design and lifestyle experiences.

"We see this as a creative, interesting solution for hotels. These are hotels that are very selective about using booking platforms," he said. "No other hotel company has done this, and it's the first channel to present the properties in a beautiful way."

The goal is to target the next generation of travelers — people who are on the go, accustomed to the convenience of on-demand apps, and who still want the very best experience possible.

And since it's coming from a hotel's perspective, Lalvani says, One Night is better-equipped to tell the story of each individual property's brand. The Standard International team curated a local guide for each of the hotels, which provides hour-by-hour suggestions of the best things to do in that neighborhood throughout the day.

Standard International takes a percentage of each booking that users make on the app. Lalvani declined to disclose the exact percentage, but said it is "more friendly to the hotels" than the cut that a traditional third-party booking service would take.

In July, Standard International introduced a new feature called Standard Time that allows guests to choose their own check-in and check-out times across all five of its properties. Once the hotel knows when guests will be checking in and out, it uses that information to schedule housekeeping and make more arrival options available to other customers.